The First Division, led by the Captain-Commander himself, acts as the administrative body of the Gotei 13 due to its history as "father" of the other divisions. While the rule of Soul Society ultimately falls to the Central 46, the control of the military in Seireitei lies with the First Division. Although they act as the Central 46's arm to a certain extent, they also draft laws and rules that apply only to the members of the Gotei 13.
The members of the First are often seen as exemplary Shinigami, adhering to rules and traditions, their manner one of dignified grace.
The Second Division, also known as the Onmitsukidō—the special forces—is traditionally known as an elite cadre of highly trained Shinigami operatives. Specializing in stealth and speed, their duties include covert operations, bodyguard details and the long-term incarceration of exceptionally problematic Shinigami.
The members of the Second are regarded as mysterious and businesslike, completing their tasks efficiently and with a high level of professionalism.
The Third Division, synonymous with the Kidōshū—the Kidō corps—is the home of those gifted in the use of the Demon Arts. The Third Division specializes in the practical and theoretical application of Kidō, its members all highly skilled practitioners of the art. Their duties also include the monitoring of the passages between Soul Society and Earth, allowing or restricting access through the Senkaimon.
Members of the Third are often intelligent, well-spoken and polite, and although the Kidōshū was originally quite reclusive, this has steadily changed over the years.
The Fourth Division houses the medical corps of the Gotei 13, the members all skilled at treating wounds and healing the injured. They act predominantly as field medics, and they maintain Seireitei's central medical facility. The Fourth Division is almost unanimously regarded as the most beneficial organization in Seireitei and it is just as—if not more—respected as the First Division.
The members of the Fourth are kind and generous, empathy being one of the core traits of the division, along with perseverance and a desire to aid those in need.
The Fifth Division has no speciality, just as it has no weakness. It prioritizes the ability to respond to any number of situations equally well, and the division is often seen as a place for new recruits fresh out of the Academy to be placed while waiting for their specific skill sets to manifest. Some make careers in the Fifth, remaining a jack of all trades their entire lives, though most are eventually moved to other divisions.
Members of the Fifth are of mixed personalities and types, a reflection of the nature of their division.
The Sixth Division acts as the Gotei 13 police, apprehending and punishing criminal or rogue Shinigami both in Soul Society and on Earth. They maintain a medium-security prison facility, though it is not intended for anything more than relatively brief punishment sentences; those who pose serious threats are held by the Second Division. Though uncommon, executions are dealt with by the Sixth Division.
Members of the Sixth typically have a burning passion for justice and order, though it is not unheard of for those seeking personal power to join the Sixth.
The Seventh Division houses those Shinigami whose skills are best applied in a supportive capacity. Their zanpakutō are often more suited for strengthening their comrades than for single combat, and because of this they are often found helping the Fourth, Ninth, or Eleventh Division with their duties or acting as a reserve force along with the Fifth.
Members of the Seventh are viewed as generous and thoughtful, but dislike standing in the spotlight. Perhaps because of this, they are almost as popular as the members of the Fourth.
Records and Reconnaissance
The Eighth Division functions as a military intelligence organization, providing reconnaissance, surveillance, and keeping records. Observant, intelligent and efficient, the division is similar to the Second Division, though its field officers are significantly less aggressive (but often equally dangerous), preferring to watch and learn without being detected. They maintain the expansive Seireitei Archive as well as sending operatives to various locales on intelligence-gathering assignments.
The members of the Eighth are regarded as omniscient, analytical, and efficient, often displaying an advanced attention to detail and an ability to work equally well with a team or alone.
The Ninth Division acts as necessary precaution against attacks directed at Seireitei. Essentially a home guard, they protect Seireitei from external threats, and as such the division is always on full alert. They often collaborate with the Sixth Division when it is necessary, though they hold no authority of their own. The division houses the most Shinigami with defensive zanpakutō, and they are proud to protect their comrades.
The members of the Ninth are bold and have a strong sense of duty, ever vigilant and always ready to respond to a threat. They are regarded as being very reliable people.
The Tenth Division is in charge of the Shinigami Academy, and also serves as a division where those who are not quite able to perform their duties as a Shinigami at a satisfactory level are placed. Because of this, the division has a reputation for housing not only some of the smartest, most able teachers and instructors in Seireitei, but also some of the most worthless bums in Soul Society. The purpose of this mix was to make sure those of limited skill were able to spend more time with those of exceptional skill, hoping it would rub off in the right direction.
Members of the Tenth are regarded with alternating reverence and ridicule, depending on which side of the intellectual fence they are on. The instructors and teachers are often remembered and highly respected from time spent in the Academy, whereas the remainder of the division is something of a laughing stock.
The Eleventh Division is the main attacking force of the Gotei 13, and is unquestionably the largest and most unruly division. While their prowess in battle is well-known, their intelligence often comes into question, as they not only display a reckless disregard for self-preservation, but also irrational amounts of bravado. The division as a whole has a fierce loyalty to the captain of their division, whose unofficial title is "Kenpachi".
Members of the Eleventh are widely seen as violent, bloodthirsty, and slightly insane, but ultimately good-natured and loyal. They speak frankly and don't take offense to much.
Research and Development
The Twelfth Division is beyond any shadow of a doubt the least social and most intelligent division of the Gotei 13. The organization is synonymous to the Shinigami Research Institute, the Captain of the division also holding the position of President of the Institute. While the division mostly keeps to itself, it supplies the Gotei 13 with large amounts of new technology that is used for a variety of purposes.
The members of the Twelfth are typically reclusive, unsocial, and quiet, hiding their brilliance behind a wall if silence. They are perceived by many as somewhat unsettling, though this does not bother them in the slightest.
The Thirteenth Division is by far the most magnanimous and socially graceful division of the Gotei 13, a polar opposite to the Twelfth Division. Acting as diplomats and representatives for Shinigami outside Soul Society, they form the relationships between Seireitei and other organizations. Like the First Division, they are partially under the direct control of the Central 46, but still maintain the normal chain of command. The division also maintains the largest presence on Earth.
Members of the Thirteenth are well-spoken, charming, polite and display exquisite manners, and are able—though seldom exceptional—soldiers.